Thermal management systems generally include an enclosure such as a housing or cabinet for heat generating electronic component circuit cards or boards which must be cooled to prevent damage to the electronic components. A variable speed fan is disposed to force air over the components and a temperature sensor and/or an air flow sensor monitors the temperature and/or air flow rate of the air or other cooling gas inside the cabinet.
A filter is used to reduce particulate matter in order to eliminate contaminants which could otherwise foul the circuit cards. A controller, connected to the fan and responsive to the temperature sensor and/or the air flow sensor, continuously monitors the temperature of the electronic circuit cards and adjusts the speed of the fan to keep the electronic components cool.
Such prior art systems, however, do not include means to determine the fan's condition or health. When the fan's bearings or motor begins to fail, the fan, operating at even full capacity, may not properly cool the electronic components and by the time this condition is detected manually, certain electronic components may have already failed, become thermally stressed, or degraded to the point where failure is imminent.
Prior art systems also fail to include any means for determining whether the filter is clogged to the point where cooling is no longer effective. Again, when the filter is clogged, the air flow rate through the cabinet may be less than optimal even at the highest fan speed resulting in component failure, thermal stress, or degradation which may not be detectable.